Doors Open Ontario

Heintzman House Doors Open Markham

Heintzman House

Heintzman House – a treasured asset of the Thornhill community – is one of the area’s oldest buildings. This historical building has a fascinating story. What began as a simple farmhouse in 1798 is now an important piece of Markham’s history and a gathering place for the community. Originally built as an adobe brick cottage, the house was enlarged by Colonel George Crookshank in 1817. Charles T. Heintzman, grandson of the founder of Toronto’s Heintzman Piano Company, purchased the property in the 1930s and transformed the house into its present, elegant form. Heintzman House was Markham’s most-visited site during Doors Open Markham 2019 and is a beautiful space for any occasion. From the preserved original architecture to the impressive seasonal gardens, Heintzman House offers something for everyone. There are also tales of prominent owners, spirits that dwell inside, and a community’s determined efforts to recognize the heritage site. During Digital Doors Open, learn about the history of this remarkable place through the video below.

Tell us your story about this site

  • Digital Doors Open
  • Video
  • Kid-friendly
  • Site is protected by the Ontario Heritage Trust

Contact info

135 Bay Thorn Drive
Markham, Ontario


Year built: 1816
Architectural style: Classical revival, Georgian, Regency
Building type: Attraction, Historical landmark, Historical house
Landscape: Garden

Dates/hours open

Friday May 1 – Wednesday March 31, 2021
Part of Digital Doors Open Markham

Heintzman House 135 Bay Thorn Drive